<template>
    <div id="app">
    <div>
      <p>请选择你要购买的书籍</p>
      <ul>
         <li v-for='item in arr' :key = 'item.id'> {{item.name}}<button @click='buy(item)'>买书</button></li>
      </ul>
      <table border="1" width="500" cellspacing="0">
          <tr>
          <th>序号</th>
          <th>书名</th>
          <th>单价</th>
          <th>数量</th>
          <th>合计</th>
        </tr>
        <tr v-for='(item,index) in arr' :key = 'item.id' >
          <td>{{index +1}}</td>
          <td>{{item.name}}</td>
          <td>{{item.price}}</td>
          <td>{{item.count}}</td>
          <td>{{item.price*item.count}}</td>
        </tr>
      </table>
      <p>总价格为:{{total}} </p>
    </div>
  </div>
</template>

<script>
// import dayjs from 'dayjs'
export default {
   data(){
      return{
         total:0,
          arr: [
        {
          name: "水浒传",
          price: 107,
          count: 0,
        },
        {
          name: "西游记",
          price: 192,
          count: 0,
        },
        {
          name: "三国演义",
          price: 219,
          count: 0,
        },
        {
          name: "红楼梦",
          price: 178,
          count: 0,
        },
      ],
      }
   },
   methods:{
      buy(c){
      c.count ++ 
      this.total = this.arr.reduce((p,n)=> p+ n.price*n.count,0 )
      }
   }
}
</script>

<style>
 
</style>